Organic acids and oligomers thereof have been shown to promote plant growth. Typical such promoters of plant growth are described by Kinnersley et al., Plant Growth Regulation 9:137-146 (1990), which publication mentions the effects of lactic acid and relatively low molecular weight oligomers of lactic acid on plant growth. Similar description is found in U.S. Pat. No. 4,813,997 to Kinnersley et al. (oligomers of glycolic and/or L-lactic acid) and U.S. Pat. No. 4,799,957 to Danzig et al. (oligomers of thiolactic and thioglycolic acids). All of the forgoing approaches to plant growth promotion appear to focus on coordination as a means for increasing plant uptake of compounds vital to the growth of the plant, e.g., micronutrients such as calcium, magnesium, sulfur, manganese, zinc, copper, iron, boron, and the like.
A very common approach to the promotion of plant growth has been, and continues to be, the use of nutrients (fertilizers), natural as well as synthetic. The latter usually provides nitrogen in a plant-usable form, such as urea for example, and/or inorganic nitrates, phosphates, or the like compounds. While such nutrients may be applied, more or less, at the convenience of the farmer, and may be applied as often as deemed desirable, the overuse of synthetic nutrients and the inefficient use of synthetic nutrients are major factors responsible for environmental problems such as eutrophication of ground water, nitrate pollution, phosphate pollution, and the like. An overview of the undesirable effects of nitrogen fertilizer is presented by Byrnes, Fertilizer Research 26:209-215 (1990).
To ameliorate the problems attendant to inefficient nutrient use and nutrient overuse, it would be desirable and necessary for environmental and production reasons to improve the collection, absorption and consolidation of plant nutrients and hold them in a condition and position to maximize availability for plant uptake while minimizing loss of nutrients or fertilizer elements through leaching, denitrification, vaporization and other mechanisms that distort or prevent assimilation of these nutrients by plant biological and physical mechanisms. The present invention addresses these problems, and provides methods for collecting or attracting plant nutrients which results in more efficient usage of nutrients in the growing plant.